/*
 * developer spirit_demon  @ 2015.
 */

package com.lookup.dynamic.ext;

import akka.actor.*;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;

/**
 * An Akka Extension to provide access to Spring managed Actor Beans.
 * source: https://github.com/typesafehub/activator-akka-java-spring
 */
public class SpringExtension extends
        AbstractExtensionId<SpringExtension.SpringExt> {

    private SpringExtension() {
    }

    // thread safety is needed
    private static class Holder {
        static final SpringExtension INSTANCE = new SpringExtension();
    }

    /**
     * The method used to access the SpringExtension.
     */
    public static SpringExtension instance() {
        return Holder.INSTANCE;
    }

    /**
     * Is used by Akka to instantiate the Extension identified by this
     * ExtensionId, internal use only.
     */
    @Override
    public SpringExt createExtension(ExtendedActorSystem system) {
        return new SpringExt();
    }

    /**
     * The lookup method is required by ExtensionIdProvider, so we return ourselves here,
     * this allows us to configure our extension to be loaded when the ActorSystem starts up
     *
     * @return extension itself
     */
    public SpringExtension lookup() {
        return SpringExtension.instance();
    }

    /**
     * The Extension implementation.
     */
    public static class SpringExt implements Extension {
        private volatile ApplicationContext applicationContext;

        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            this.applicationContext = applicationContext;
        }

        /**
         * Create a Props for the specified actorBeanName using the
         * SpringActorProducer class.
         *
         * @param actorBeanName The name of the actor bean to create Props for
         * @return a Props that will create the named actor bean using Spring
         */
        public Props create(String actorBeanName) {
            return Props.create(SpringActorProducer.class,
                    applicationContext, actorBeanName);
        }

        /**
         * Create a Props for the specified actorBeanName using the
         * SpringActorProducer class.
         *
         * @param requiredType Type of the actor bean must match. Can be an interface or superclass
         *                     of the actual class, or {@code null} for any match. For example, if the value
         *                     is {@code Object.class}, this method will succeed whatever the class of the
         *                     returned instance.
         * @return a Props that will create the actor bean using Spring
         */
        public Props create(Class<?> requiredType) {
            return Props.create(SpringActorProducer.class,
                    applicationContext, requiredType);
        }

        /**
         * Create a Props for the specified actorBeanName using the
         * SpringActorProducer class.
         *
         * @param actorBeanName The name of the actor bean to create Props for
         * @param requiredType  Type of the actor bean must match. Can be an interface or superclass
         *                      of the actual class, or {@code null} for any match. For example, if the value
         *                      is {@code Object.class}, this method will succeed whatever the class of the
         *                      returned instance.
         * @return a Props that will create the actor bean using Spring
         */
        public Props create(String actorBeanName, Class<? extends UntypedActor> requiredType) {
            return Props.create(SpringActorProducer.class,
                    applicationContext, actorBeanName, requiredType);
        }
    }
}